The present invention is directed to a device for capturing or entrapping, guiding and focusing light which utilizes a synthetic member containing a fluorescent material which scatters and converts ambient light into fluorescent light which can be subsequently coupled therefrom.
A passive display device, which has light valves and has a device including a fluorescent material for capturing, guiding and concentrating light for coupling out through outlet windows which are aligned with the light valves, is known and an example is disclosed in U.S. Pat. No. 4,142,781, which includes the disclosure of German Patent Application No. 25 54 226. As pointed out in this Patent, whose disclosure is incorporated by reference, a synthetic body in the design of a plate contains a fluorescent material and serves to increase the intensity of the passive display device, for example, a liquid crystal display. This plate for example will capture the ambient light, convert it into fluorescent light, and guide it to coupling out or exit windows, which are arranged in the surface of the plate in the pattern of the display segments. These coupling out windows or exit windows can be formed by notches, impressed pigment layers or roughening of the surface.
The plate with the light emitted through the outlet windows serves as a background illumination for a liquid crystal display. To provide a good readability for the display, the illuminous density of the device should be as great as possible.